/*
   md5.h - Declaration of functions and data types used for MD5 sum
   computing library functions.
   Copyright (C) 1995, 1996, 1999 Free Software Foundation, Inc.
   NOTE: The canonical source of this file is maintained with th GNU C
   Library.  Bugs can be reported to bug-glibc@prep.ai.mit.edu.

   This program is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by the
   Free Software Foundation; either version 2, or (at your option) any
   later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  
*/

/* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. */
/* Hacked to work with vivi by Janghoon Lyu <nandy@mizi.com>, 2002.  */

#include <config.h>
#include <machine.h>
#include <md5.h>
#include <command.h>
#include <printk.h>
#include <vivi_string.h>
#include <string.h>

#undef WORDS_BIGENDIAN
#ifdef WORDS_BIGENDIAN
# define SWAP(n) \
	(((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
#else
# define SWAP(n) (n)
#endif

/*
 * This array contains the bytes used to pad the buffer to the next
 * 64-byte boundary. (RFC 1321, 3.1: Step 1) 
 */
static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };

/*
 * Initialize structure containig state of computation.
 * (RFC 1321, 3.3: Step 3)
 */
void
md5_init_ctx(struct md5_ctx *ctx)
{
	ctx->A = 0x67452301;
	ctx->B = 0xefcdab89;
	ctx->C = 0x98badcfe;
	ctx->D = 0x10325476;

	ctx->total[0] = ctx->total[1] = 0;
	ctx->buflen = 0;
}

/*
 * Put result from CTX in first 16 bytes following RESBUF. The result
 * must be in little endian byte order.
 *
 * IMPORTANT: On some systems it is required that RESBUF is correctly
 * aligned for a 32 bits value.
 */
void *
md5_read_ctx(const struct md5_ctx *ctx, void *resbuf)
{
	((md5_uint32 *)resbuf)[0] = SWAP(ctx->A);
	((md5_uint32 *)resbuf)[1] = SWAP(ctx->B);
	((md5_uint32 *)resbuf)[2] = SWAP(ctx->C);
	((md5_uint32 *)resbuf)[3] = SWAP(ctx->D);

	return resbuf;
}

/*
 * Process the remaining bytes in the internal buffer and the usual
 * prolog according to the standard and write the result to RESBUF.
 *
 * IMPORTANT: On some systems it is required that RESBUF is correctly
 * aligned for a 32 bits value.
 */
void *
md5_finish_ctx(struct md5_ctx *ctx, void *resbuf)
{
	/* Take yet unprocessed bytes into account. */
	md5_uint32 bytes = ctx->buflen;
	size_t pad;

	/* Now count remaining bytes. */
	ctx->total[0] += bytes;
	if (ctx->total[0] < bytes)
		++ctx->total[1];

	pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
	memcpy(&ctx->buffer[bytes], fillbuf, pad);

	/* Put the 64-bit file length in *bits* at the end of the buffer. */
	*(md5_uint32 *)&ctx->buffer[bytes + pad] = SWAP(ctx->total[0] << 3);
	*(md5_uint32 *)&ctx->buffer[bytes + pad + 4] = SWAP((ctx->total[1] << 3) |
							    (ctx->total[0] >> 29));

	/* Process last bytes. */
	md5_process_block(ctx->buffer, bytes + pad + 8, ctx);

	return md5_read_ctx(ctx, resbuf);
}

/*
 * Compute MD5 message digest for bytes read from STREAM. The
 * resulting message digest number will be written into the 16 bytes
 * beginning at RESBLOCK.
 */
#if 0
int
md5_stream(FILE *tream, void *resblock)
{
	/* Important: BLOCKSIZE must be a multiple of 64. */
#define BLOCKSIZE 4096
	struct md5_ctx ctx;
	char buffer[BLOCKSIZE + 72];
	size_t sum;

	/* Initialize the computation context. */
	md5_init_ctx(&ctx);

	/* Iterate over full file contents. */
	while (1) {
		/* 
		 * We read the file in blocks of BLOCKSIZE bytes. One call of the
		 * computation function processes the whole buffer so that with
		 * the next round of the loop another block can be read.
		 */
		size_t n;
		sum = 0;

		/* Read block. Take care for partial reads. */
		do {
			n = fread(buffer + sum, 1, BLOCKSIZE - sum, stream);
			sum += n;
		} while (sum < BLOCKSIZE && n != 0);
		if (n == 0 && ferror(stream))
			return 1;

		/* If end of file is reached, end the loop. */
		if (n == 0)
			break;

		/*
		 * Process buffer with BLOCKSIZE bytes. Note that
		 * BLOCKSIZE % 64 == 0
		 */
		md5_process_block(buffer, BLOCKSIZE, &ctx);
	}

	/* Add the last bytes if necessary. */
	if (sum > 0)
		md5_process_bytes(buffer, sum, &ctx);

	/* Construct result in desired memory. */
	md5_finish_ctx(&ctx, resblock);
	return 0;
}
#endif

/*
 * Compute MD5 message digest for LEN bytes beginning at BUFFER. The
 * result is always in little endian order, so that a byte-wise
 * output yields to the wanted ASCII representation of the message
 * digest.
 */
void *
md5_buffer(const char *buffer, size_t len, void *resblock)
{
	struct md5_ctx ctx;

	/* Initialize the computation context. */
	md5_init_ctx(&ctx);

	/* Process whole buffer but last len % 64 bytes. */
	md5_process_bytes(buffer, len, &ctx);

	/* Put result in desried memory area. */
	return md5_finish_ctx(&ctx, resblock);
}


void
md5_process_bytes(const void *buffer, size_t len, struct md5_ctx *ctx)
{
	/*
	 * When we already have some bits in our internal buffer concatenate
	 * both inputs first.
	 */
	if (ctx->buflen != 0) {
		size_t left_over = ctx->buflen;
		size_t add = 128 - left_over > len ? len : 128 - left_over;

		memcpy(&ctx->buffer[left_over], buffer, add);
		ctx->buflen += add;

		if (left_over + add > 64) {
			md5_process_block(ctx->buffer, (left_over + add) & ~63, ctx);
			/* The regions in the following copy operation cannot overlab. */
			memcpy(ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
				(left_over + add) & 63);
			ctx->buflen = (left_over + add) & 63;
		}

		buffer = (const char *)buffer + add;
		len -= add;
	}

	/* Process available complete blocks. */
	if (len > 64) {
		md5_process_block(buffer, len & ~63, ctx);
		buffer = (const char *)buffer + (len & ~63);
		len &= 63;
	}

	/* More remaining bytes in internal buffer. */
	if (len > 0) {
		memcpy(ctx->buffer, buffer, len);
		ctx->buflen = len;
	}
}

/* 
 * These are the four functions used in the four steps of the MD5 algorithm
 * and defined in the RFC 1321. The first function is a little bit optimized
 * (as found in Colin Plumbs public domain implementation). 
 */
/* #define FF(b, c, d)	((b & c) | (~b & d)) */
#define FF(b, c, d)	(d ^ (b & (c ^ d)))
#define FG(b, c, d)	FF(d, b, c)
#define FH(b, c, d)	(b ^ c ^ d)
#define FI(b, c, d)	(c ^ (b | ~d))

/*
 * Process LEN bytes of BUFFER, accumulating context into CTX.
 * It is assumed that LEN % 64 == 0.
 */

void
md5_process_block(const void *buffer, size_t len, struct md5_ctx *ctx)
{
	md5_uint32 correct_words[16];
	const md5_uint32 *words = buffer;
	size_t nwords = len / sizeof(md5_uint32);
	const md5_uint32 *endp = words + nwords;
	md5_uint32 A = ctx->A;
	md5_uint32 B = ctx->B;
	md5_uint32 C = ctx->C;
	md5_uint32 D = ctx->D;

	/*
	 * First increment the byte count. RFC 1321 specifies the possible
	 * length of the file up to 2^64 bits. Here we only compute the
	 * number of bytes. Do a double word increment
	 */
	ctx->total[0] += len;
	if (ctx->total[0] < len)
		++ctx->total[1];

	/*
	 * Process all bytes in the buffer with 64 bytes in each round of
	 * the loop.
	 */
	while (words < endp) {
		md5_uint32 *cwp = correct_words;
		md5_uint32 A_save = A;
		md5_uint32 B_save = B;
		md5_uint32 C_save = C;
		md5_uint32 D_save = D;

		/*
		 * First round: using the given function, the context and a constant
		 * the next context is computed. Because the algorithms processing
		 * unit is a 32-bit word and it is determinied to work on words in
		 * little endian byte order we perhaps have to change the byte order
		 * before the computation. To reduce the work for the next steps
		 * we store the swapped words in the array CORRECT_WORDS.
		 */

#define OP(a, b, c, d, s, T)						\
	do  {								\
		a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T;	\
		++words;						\
		a = rol (a, s);						\
		a += b;							\
	} while (0)

		/*
		 * Before we start, one word to the strange constants.
		 * They defined in RFC 1321 as
		 *
		 * T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64, or
		 * perl -e 'foreach(1..64){printf "0x%08x\n", int (4294967296 * abs (sin $_))}'
		 */

		/* Round 1.  */
		OP(A, B, C, D,  7, 0xd76aa478);
		OP(D, A, B, C, 12, 0xe8c7b756);
		OP(C, D, A, B, 17, 0x242070db);
		OP(B, C, D, A, 22, 0xc1bdceee);
		OP(A, B, C, D,  7, 0xf57c0faf);
		OP(D, A, B, C, 12, 0x4787c62a);
		OP(C, D, A, B, 17, 0xa8304613);
		OP(B, C, D, A, 22, 0xfd469501);
		OP(A, B, C, D,  7, 0x698098d8);
		OP(D, A, B, C, 12, 0x8b44f7af);
		OP(C, D, A, B, 17, 0xffff5bb1);
		OP(B, C, D, A, 22, 0x895cd7be);
		OP(A, B, C, D,  7, 0x6b901122);
		OP(D, A, B, C, 12, 0xfd987193);
		OP(C, D, A, B, 17, 0xa679438e);
		OP(B, C, D, A, 22, 0x49b40821);

      /* For the second to fourth round we have the possibly swapped words
         in CORRECT_WORDS.  Redefine the macro to take an additional first
         argument specifying the function to use.  */
#undef OP
#define OP(f, a, b, c, d, k, s, T)				\
	do {							\
		a += f (b, c, d) + correct_words[k] + T;	\
		a = rol (a, s);					\
		a += b;						\
        } while (0)

		/* Round 2.  */
		OP(FG, A, B, C, D,  1,  5, 0xf61e2562);
		OP(FG, D, A, B, C,  6,  9, 0xc040b340);
		OP(FG, C, D, A, B, 11, 14, 0x265e5a51);
		OP(FG, B, C, D, A,  0, 20, 0xe9b6c7aa);
		OP(FG, A, B, C, D,  5,  5, 0xd62f105d);
		OP(FG, D, A, B, C, 10,  9, 0x02441453);
		OP(FG, C, D, A, B, 15, 14, 0xd8a1e681);
		OP(FG, B, C, D, A,  4, 20, 0xe7d3fbc8);
		OP(FG, A, B, C, D,  9,  5, 0x21e1cde6);
		OP(FG, D, A, B, C, 14,  9, 0xc33707d6);
		OP(FG, C, D, A, B,  3, 14, 0xf4d50d87);
		OP(FG, B, C, D, A,  8, 20, 0x455a14ed);
		OP(FG, A, B, C, D, 13,  5, 0xa9e3e905);
		OP(FG, D, A, B, C,  2,  9, 0xfcefa3f8);
		OP(FG, C, D, A, B,  7, 14, 0x676f02d9);
		OP(FG, B, C, D, A, 12, 20, 0x8d2a4c8a);

		/* Round 3.  */
		OP(FH, A, B, C, D,  5,  4, 0xfffa3942);
		OP(FH, D, A, B, C,  8, 11, 0x8771f681);
		OP(FH, C, D, A, B, 11, 16, 0x6d9d6122);
		OP(FH, B, C, D, A, 14, 23, 0xfde5380c);
		OP(FH, A, B, C, D,  1,  4, 0xa4beea44);
		OP(FH, D, A, B, C,  4, 11, 0x4bdecfa9);
		OP(FH, C, D, A, B,  7, 16, 0xf6bb4b60);
		OP(FH, B, C, D, A, 10, 23, 0xbebfbc70);
		OP(FH, A, B, C, D, 13,  4, 0x289b7ec6);
		OP(FH, D, A, B, C,  0, 11, 0xeaa127fa);
		OP(FH, C, D, A, B,  3, 16, 0xd4ef3085);
		OP(FH, B, C, D, A,  6, 23, 0x04881d05);
		OP(FH, A, B, C, D,  9,  4, 0xd9d4d039);
		OP(FH, D, A, B, C, 12, 11, 0xe6db99e5);
		OP(FH, C, D, A, B, 15, 16, 0x1fa27cf8);
		OP(FH, B, C, D, A,  2, 23, 0xc4ac5665);

		/* Round 4.  */
		OP(FI, A, B, C, D,  0,  6, 0xf4292244);
		OP(FI, D, A, B, C,  7, 10, 0x432aff97);
		OP(FI, C, D, A, B, 14, 15, 0xab9423a7);
		OP(FI, B, C, D, A,  5, 21, 0xfc93a039);
		OP(FI, A, B, C, D, 12,  6, 0x655b59c3);
		OP(FI, D, A, B, C,  3, 10, 0x8f0ccc92);
		OP(FI, C, D, A, B, 10, 15, 0xffeff47d);
		OP(FI, B, C, D, A,  1, 21, 0x85845dd1);
		OP(FI, A, B, C, D,  8,  6, 0x6fa87e4f);
		OP(FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
		OP(FI, C, D, A, B,  6, 15, 0xa3014314);
		OP(FI, B, C, D, A, 13, 21, 0x4e0811a1);
		OP(FI, A, B, C, D,  4,  6, 0xf7537e82);
		OP(FI, D, A, B, C, 11, 10, 0xbd3af235);
		OP(FI, C, D, A, B,  2, 15, 0x2ad7d2bb);
		OP(FI, B, C, D, A,  9, 21, 0xeb86d391);

		/* Add the starting values of the context.  */
		A += A_save;
		B += B_save;
		C += C_save;
		D += D_save;
	}

	/* Put checksum in context given as argument.  */
	ctx->A = A;
	ctx->B = B;
	ctx->C = C;
	ctx->D = D;
}


/*
 * for vivi
 */

int
md5_buffer_stream(const char *buffer, size_t len, void *resblock)
{
/* Important: BLOCKSIZE must be a multiple of 64. */
#define TMP_BUF_SIZE 4096
	struct md5_ctx ctx;
	char tmp_buffer[TMP_BUF_SIZE + 72];
	size_t sum = 0;

	md5_init_ctx(&ctx);

	while (1) {
		if (len < TMP_BUF_SIZE)
			break;

		memcpy(tmp_buffer, buffer + sum, TMP_BUF_SIZE);

		md5_process_block(tmp_buffer, TMP_BUF_SIZE, &ctx);

		sum += TMP_BUF_SIZE;
		len -= TMP_BUF_SIZE;
	}

	if (len > 0)  {
		memcpy(tmp_buffer, buffer + sum, len);
		md5_process_bytes(tmp_buffer, len, &ctx);
	}

	md5_finish_ctx(&ctx, resblock);

	return 0;
}

void
check_md5sum(const char *buf, size_t len, char *file_name)
{
	unsigned char bin_buffer[16];
	int cnt;

	printk("MD5SUM:  ");
	md5_buffer(buf, len, bin_buffer);
	for (cnt = 0; cnt < 16; cnt++)
		printk("%02x", bin_buffer[cnt]);
	if (file_name != NULL)
		printk("  %s", file_name);
	printk("\n");
}

void command_md5sum(int argc, const char **argv)
{
	size_t len;
	char *buffer;
	unsigned char resbuf[16];
	int i;

	if (argc != 3) {
		printk("invalid 'sleep' command: too few(many) arguments\n");
		return;
	}

	if (strncmp("downfile", argv[1], 8) == 0) {
		buffer = (char *)RAM_BASE;
	} else {
		buffer = (char *)strtoul(argv[1], NULL, 0, NULL);
	}

	len = (size_t)strtoul(argv[2], NULL, 0, NULL);

	printk("address = 0x%x, size = %d bytes\n", buffer, len);

	md5_buffer(buffer, len, resbuf);

	printk("MD5SUM:  ");
	for (i = 0; i < 16; i++)
		printk("%02x", resbuf[i]);
	printk("\n");

}


user_command_t md5sum_cmd = {
	"md5sum",
	command_md5sum,
	NULL,
	"md5sum <addr> <size> | downfile <size>\t-- Compute MD5"
};
